public class MainActivity extends AppCompatActivity {
    private ArrayAdapter<String> adapter;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Spinner spinner = (Spinner) findViewById(R.id.phone_spinner);
        adapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item);
        adapter.add("45656");
        adapter.add("stsat");
        adapter.add("asskjt");
        adapter.add("444");
        spinner.setAdapter(adapter);
    }
    
    public void sort(View view) {
        Spinner spinner = (Spinner) findViewById(R.id.phone_spinner);
        int count = adapter.getCount();
        String[] a = new String[count];
        String b;
        for (int i = 0; i < count; i++) {
            a[i] = adapter.getItem(i);
            if (adapter.getItem(i).compareTo(adapter.getItem(i + 1)) > 0)
            {
                a[i] = a[i+1];
                b = a[i];
                a[i+1] = b;
            }
        }
        adapter.notifyDataSetChanged();
    }
}이렇게 sort를 할려고하는대 제가보기에는 문제가없어보이는 sort라는 버튼을 눌르면 문제가생깁니다.